3. The abdomen-case consists of _nine_ segments when viewed on the back, and of only _six_ when viewed below; so that it might be said to have ten dorsal and six ventral segments: but the fact is, that the place of the three anterior ventral segments, or rather ventral portions of the segments, (for they form complete rings without any lateral suture,) are replaced by the wings and other organs: in consequence of this, the fourth segment, which is less covered than the three first, at its posterior margin forms an annulus or ring. In counting the abdominal segments of a pupa, you must be careful not to include the piece that represents the _metathorax_, which looks as if it belonged to the abdomen[588]. In the pupæ of _butterflies_ you will discover evident traces of _ten_ dorsal segments; but in many _moths_, and some _hawk-moths_, you will perceive at first only _eight_, or even _seven_, but a closer examination will enable you to discover the line that marks out the others; and if you divide the puparium longitudinally, and inspect its internal surface, you will see very visible sutures between them. The intermediate segments are sometimes separated from each other and the preceding and subsequent ones by deep channels. In the pupa of _Papilio Machaon_ there is one such channel between the third and fourth segments. In _Bombyx regalis_ the channel is between the sixth and seventh, and in _B. imperatoria_ there are three, namely, a channel between the third and fourth, and fourth and fifth, and fifth and sixth segments. The way in which insects with an exserted sting fold it in the pupa seems not to have been noticed; but from an observation of De Geer upon one species of _Ichneumon_, it appears to be turned up over the back of the abdomen[589].
These little animals, thus swathed and banded, exhibit no unapt representation of an Egyptian mummy; though Lamarck applies the term _Mumia_ to _incomplete_ pupæ[590], to which it seems less happily applicable.
Chrysalises, as to the modifications of their general figure, may be conveniently divided into two great classes: _first_, those that have no angular projections, the anal mucro of some excepted, on different parts of their body; and _secondly_, those which have such projections. Each of these classes affords variations in its peculiar characters which require to be noticed.